Rescaling question

[Delwin D Fandrich]

PNOTNR@aol.com wrote:

> You read my mind!  That was my next question.
>
> I've been able to lower my original attempt numbers.  I currently have a scale
> that is only 375 lbs higher then what I started with.  And I strongly suspect
> that the instrument does not have its original bass strings (the unwrapped
> ends by the agraffes are all 1 1/4" long) so maybe this piano had a higher
> tension when it was built.  But I WAS wondering about the redistribution of
> tension.
>
> Am I correct in thinking that even if a hitch pin for a bass string is
> immediately behind one for a treble string, changing the tension on one won't
> have an effect on the other (because the tension is inline with the string)?
>
> Gordon Large, RPT
> Maine

  ----------------------------

Changing the "tension" on one won't have an effect on the "tension" of the other,
but they both may be affecting the same plate strut.  With all piano plates you
have to try to visualize the stresses that each strut has to support.  Mostly this
is a matter of common sense.  And practice.

While I've personally never broken a plate after redesigning a stringing scale, I
have fixed several.  Those that I have seen have all broken at the bass/tenor
strut just behind the point where the "V" comes together.  If memory serves, those
plate struts were relative thin at this point.  And here is the rub.  Without some
experience at examining plates how do you tell if one plate is particularly weak
-- relative to what?  The only advice I can give here is to look at a lot of them
and think.  After all, what else can you do while you're tuning?  Spend the time
educating yourself.

With the piano and the scale you've described you're probably safe.  Just keep in
mind that this is an on-going education process.  Use every one of these jobs as
an opportunity to learn something new.

Regards,

Del